StackExchange is the most popular and professional IT Q&A site, Under StackExchange, there is StackOverflow and other sub sites. Many of us may wonder how this mega site is maintained and what its performance is. A performance page has been released by StackExchange recently.Below is some statistic about this mega site.560 million page views per month, i.e around 1.9 million PVs per day.For such as big site, it has only 9 web servers and 4 SQL servers(while two of them are in backup mode)185 requests per second, 559 million SQL queries per day with peak rate at 10,700 queries/secTwo redis ...

When developing projects, there are always some common work should be accomplished, for example, encrption/decryption, get IP. As a PHP developer, you should have a list of the handy functions in your toolkit so that you can pick up in every project you work on. Here is a summary of some handy PHP functions.1. PHP encryption/decryptionEncryption/decryption can be used when storing user confidential information such as passwords. Below function uses base64 and MD5 to accomplish encryption/decryption.function encryptDecrypt($key, $string, $decrypt){ if($decrypt){ $decrypted = rtrim(m...

In programming languages such as JavaScript, c/c++, Java and Matlab, you will find that you will get unexpected result when doing float point calculation. For example, when calculating 0.1 + 0.1, you will not get 0.3:> 0.1 + 0.2 == 0.3false> 0.1 + 0.20.30000000000000004Don't be surprised of this result, this is the end result of IEEE 754 standard, float point number cannot be accurately represented according to IEEE 754 because:No enough memory is allocated for representing the numberIt needs a range to ensure the accuracyJavaScript uses 64-bit floating point representation, which is the...

Contact forms are a very common part of any website and anybody can overlook them. Generally people try to choose it as their first solution but they do not realize that they are actually hurting the growth of their business.WordPress currently power more than 66 million websites but it would be good if your website is existing because of one of the most popular Content Management Systems of the world. Everyone starting from blogger to the person sitting next door use this tool for making their website look more amazing.Because of this it looks very easy to browse your plugin directory, findin...

Security is a very important aspect of programming. There are many functions or modules in any kind of real programming language providing security functionalities  In modern websites, we may often get inputs form users all around the world.There is a famous saying which says that never trust user input. So in web programming languages, we will often see functions which will guarantee the security of the data input from users. Today we will cover some of these functions in the most famous open source language  - PHP.In PHP, there are few useful functions which is very handy for preve...

IT companies are focusing more on .net for application development. This is because; the .net platform empowers developers with a wide range of tools and libraries to create diverse applications in an easy and efficient manner. The dot net framework allows users i.e. developers, to design and develop applications that can interact with web services and a range of online devices..Net programming language is richer than others in many contexts. It has several objects oriented features like properties, generics and delegates, to name a few. Besides .Net has also played a pivotal role in bringing ...

Sometimes when we do CSS on HTML elements. We may want to hide some text when the text in a specified box overflows. Usually, we can use a CSS property overflow:hidden to hide the text so that the format of the whole element will not be affected. But will it always work?I believe some of us may encounter problems when we want to hide some text in a table td cell with specified width. If we use td { overflow:hidden;}, it is supposed to hide the text if the text in a td cell overflows. But the fact is that it will fail to work.The outcome will be the height of the td cell will increase so that t...

Don’t ever let anyone tell you that looks don’t matter and it’s what’s inside that counts. Would you be eager to open a present that does not seem too promising on the outside, even when knowing what it hides may pleasantly surprise you? Right – it’s about the whole package. It may be the content on the site that creates value and makes a visitor stop for longer, but the background that accompanies it definitely plays a major role, too. Now that you’re aware of it, don’t just randomly choose any color of the rainbow to represent your page. Instea...